基于89C55和FPGA的频率特性测试仪  

Frequency Characteristic Tester Based on 89C55 and FPGA

作　　者：李璐[1] 李腾飞[1] 李飞飞[1] 

机构地区：[1]武汉大学电子信息学院,湖北武汉430079

出　　处：《现代电子技术》2011年第14期179-182,共4页Modern Electronics Technique

摘　　要：为了能够直接显示待测网络的幅频相频特性,设计了一个以89C55和FPGA构成的最小系统为控制核心的频率特性测试仪。系统基于DDS(直接数字频率合成)原理和多周期同步计数相位测量法,由信号发生器,被测双T网络,真有效值检波,相位检测,LCD显示及幅频特性曲线显示等部分构成。其中,信号发生和相位检测在FPGA内部实现。用户可通过按键输入需求,频率特性曲线实时显示于示波器上。整个系统性能稳定,界面友好,操作简单,实现了数字化频率特性分析。In order to show the amplitude-frequency phase-frequency characteristics of the network under test directly, a frequency tester using 89C55 and FPGA as control core is designed. The system is based on DDS （Direct Digital Synthesis） principle and multi-cycle synchronous counting phase measurement method, and consists of the signal generator, the measured double-T network, RMS detection, phase detection, LCD display and amplitude-frequency characteristic curve display parts. Among them, the signal generator and phase detection is realized in FPGA. Users can use key to input demand and the fre- quency characteristic curve can be displayed on the oscilloscope real-timly. The entire system has stable performance, friendly interface and simple operation. It has achieved the digital frequency analysis.

关 键 词：89C55 FPGA DDS 真有效值检波 相位测量 

分 类 号：TN919-34[电子电信—通信与信息系统] TM935[电子电信—信息与通信工程]